S12 Depression

Question 1

what are the features of depression

Answer 1

patient has symptoms continually for 2 weeks and consists of core symptoms (low mood, lack of energy and interest), depressive thoughts, biological symptoms (e.g weight loss)
depressive symptoms develop gradually, and the person has low energy and sleep disturbance

Question 2

what are the brain structures involved in Depression

Answer 2

Limbic system (emotion and memory)
Frontal lobe ( motor function, language, reasoning)
Basal ganglia ( motor and psychological function)

Question 3

what are the neurotransmitters involved in depression

Answer 3

the two main neurotransmitters for depressive disorders are :
Noradrenaline and Serotonin. There is also Dopa, Ach, GABA, glut

Question 4

how is noradrenaline made and what is it responsible for ?

Answer 4

made in the locus coeruleus in the brainstem and transported to several areas of the cortex. tyrosine is converted into L-dopa then to NA in the presynaptic membrane, NA is released into the synaptic cleft and binds to receptors.
responsible for mood and behaviour arousal (alpha 1 + 2, B 1 + 2 unknown action) functions in brain

Question 5

how is noradrenaline affected in depression ?

Answer 5

AMPT inhibits the conversion of tyrosine to L-Dopa and thus NA so there is less NA in synaptic cleft causing depressive symptoms e.g sleepy, angry
anti-depressants are used in treatment e.g NARI , which recycles any NA that doesnt bind to synaptic receptors

Question 6

how is serotonin made

Answer 6

in the brain its involved in sleep, appetite and mood.
produced in brainstem and transported to cortical areas and limbic system. There are many different serotonin receptors which ST binds to after entering the cleft

Question 7

how is serotonin affected in depression

Answer 7

there is 5HIAA depletion in CSF ( a metabolite of serotonin) and tryptophan depletion (precursor of serotonin)
Antidepressants : SSRI, TCA

Question 8

what are the causes of depression

Answer 8

Predisposing : 
genetics
childhood experiences e.g bullying
female gender e.g childcare is stressful
Perpetuating (maintaining) : 
stressful job or unemployment, studies and relationships
Precipitating factors : 
Life event e.g family death

Question 9

what is the treatment for depression

Answer 9

aim is to restore brain function ; medications directly affect brains biochemistry, social interventions such as CBT reasonably affect it

Question 10

what is psychosis

Answer 10

the presence of hallucinations or delusions

organic psychosis can be caused by infection, alcohol. Iatrogenic : steroids, L-DOPA

Question 11

what are hallucinations

Answer 11

perception without a stimulus, can by hyponogonic (state before sleep) or hypnopompic ( state before waking up)

Question 12

what is schizoprenia ?

Answer 12

mental disorder characterised by abnormal social behaviour and understanding

Question 13

how does schizoprenia present ?

Answer 13

First symptoms : Auditory hallucinations : hear thoughts
Passivity experiences ; actions feel as if they are controlled, Thought withdrawal, broadcast or insertion ; thoughts are being removed, broadcasted or implanted, Delusional perceptions ; strange thoughts, Somatic hallucinations ; feels things inside themselves
positive symptoms (added symptoms) : delusions, hallucinations 
negative symptoms (ones that take away) : underactivity, low motivation

Question 14

how is schizoprenia diagnosed

Answer 14

ICD 10 diagnosis : from symptoms such as ; thought echo, delusions hallucinations, catatonic behaviour (abnormal movements)

Question 15

what are the types of schizoprenia ?

Answer 15

Paranoid : delusions or hallucinations prominent
Simple : loss of interest, social withdrawal
Hepephrenic : aimless behaviour, speech affected
Undifferentiated
Catatonic : abnormal movements

Question 16

what is the pathophysiology of schizoprenia ?

Answer 16

Mesolimbic pathway: from ventral tegmental area to limbic structures and nucleus accumbens. this reward pathway is overactive
Mesocortical pathway : from ventral tegmental area to frontal cortex and cingulate cortex. this motivation is underactive
brain changes : enlarged ventricles, reduced hippocampus/amygdala
antibodies bind to NMDA receptor causing hypofunction, treat with corticosteroids

Question 17

what is the treatment for psychosis ?

Answer 17

typical antipsychotics : block D2 receptors, act on mesolimbic and mesocortical pathways
Atypical antipsychotics : low affinity for D2 receptors (milder side effects)
- D2 receptors are Gi receptors, so inhibit cAMP and are found in : caudate nucleus and putamen, substantia nigra and pituitary gland
side effects : dystonia (cant talk), parkinsonism
so overall, less dopamine therefore less movement
dopamine usually promotos movement, in schizoprenia we have catatonia due to less GABA binding so loss of inhibitory effect
Prognosis : generally good but increased mortality, higher incidence of CVS/resp disease

Question 18

what is drug induced psychosis ?

Answer 18

psychosis induced by a psychoactive substance e.g methamphetamine, cannabis, cocaine
ICD 10 criteria :
onest of psychotic symptoms within two weeks of substances abuse
persistence of psychotic symptoms > 48 hours
duration of disorder not exceeding 6 months

Question 19

what is affective psychosis ?

Answer 19

psychotic experiences are normally congruent with mood (in sync) for example, depressed patients may have delusions of guilt or unpleasant auditory hallucinations

Question 20

what is post partum psychosis ?

Answer 20

needs to be recognised quickly to avoid harm to mother or baby
can present in patients with no previous psychiatric history. more common if previous bipolar disorder or psychotic illness
onset within days to weeks of delivery